How to Hydrate the Right Way

A registered dietitian walks you through what, when, and how much hydration you need.


What’s in your water bottle? Water photo via Shutterstock

To say that hydration is important is hardly breaking news; it’s something that everybody has known since middle school gym class. But when it comes to explaining exactly why it’s important, not to mention how to do it right, many people are at a loss.

Laura Hartung, a registered dietitian working in Boston, says that staying hydrated is good for your heart, brain, skin, mood, metabolism, and energy levels. “Proper hydration is important for an array of duties, such as removing waste through urine, controlling body temperature, maintaining a healthy metabolism, and controlling heart rate and blood pressure.” Hartung also says that staying hydrated can also help keep weight down, because drinking water can often satisfy the same urge as unnecessary snacking.

As for the old eight cups a day debate, Hartung says there isn’t a magic number for hydration, but eight cups is a good rule of thumb for minimum amount of water per day. “The exact amount of water or fluid needed per day is very individualized,” she says. “It depends on how physically active the individual is.” Hartung recommends drinking two cups of water for every pound lost when doing strenuous exercise, and stresses that it’s important to drink before you’re thirsty to maintain ideal hydration.

But knowing why hydration is important is only half the battle; there’s still the question of what to drink. And with supermarket shelves more packed than ever with new beverage options, we asked Hartung for her take.

Water: It should go without saying that water is the best hydrator, and the best way to drink fluids throughout the day without upping your calorie intake. If plain old water bores you, Hartung recommends adding fruit or cucumber to add flavor.

Seltzer: Since seltzer is just carbonated water, Hartung says it’s also a great way to get your daily fluid intake, but cautions against drinking it during or after a workout. “Bubbles can lead to an upset stomach if consumed after exercising and may lead to feeling full and not drinking enough to replenish for proper hydration,” she says.

Tea: Despite what you’ve heard about tea being a diuretic, Hartung says it still counts toward your daily fluid intake, and even contains antioxidants. But, like seltzer, Hartung doesn’t recommend tea for the gym. “Tea does not contain electrolytes or carbohydrates to replenish,” she explains.

Sports drinks: The only time water shouldn’t be your go-to hydrator, Hartung says, is after an intense workout lasting 60 to 90 minutes—that’s where sports drinks like Gatorade and Powerade come in, since they contain the electrolytes and carbohydrates the body needs during recovery. That said, these drinks are best left at the gym. “[They have a] high sugar content, contain artificial dyes, and Powerade Zero contains artificial sweeteners like Sucralose which can increase cravings for sweet foods,” she says.

Coconut water: Coconut water is all the rage right now, but Hartung says to tread lightly. Though coconut water is typically lower in sugar and calories than sports drinks, it’s also lower in the sodium, carbohydrates, and protein that make sports drinks effective. “It does provide hydration, but water has no calories and costs less,” she says. “Limit to one coconut water per day because it does contain calories.”

Chocolate milk: Get ready to go back to kindergarten, because Hartung says chocolate milk is a great post-workout option. “Its combo of B vitamins, calcium, carbs, and protein make this great post-exercise,” she says. “It’s a catchall recovery drink: carbs and protein perfect for replenishing tired muscles [and] its high water content replaces fluid lost.” Of course, it does contain sugar and fat, so drink it in moderation if you’re watching calories. A lot of marathoners like NKOTB’s Joey McIntrye love chocolate milk after a race.

Juice: While Hartung explains that any fluid counts toward your daily total, she says to avoid juice unless it’s fresh squeezed or not from concentrate since most store-bought varieties are high in sugar and calories. “I always tell people to eat their fruit, not drink it,” she says. “Fruit contains water that can be counted toward your daily fluid intake and provides more fiber and volume that can help fill you up.”